deletegradeunit1.pas

一个功能完美的学生成绩管理系统 使用ACCESS数据库在DATA文件夹中 功能强大

unit deletegradeUnit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Mask, DBCtrls, StdCtrls, Buttons, ExtCtrls, Grids, DBGrids;

type
  TdeletegradeForm = class(TForm)
    Panel1: TPanel;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Edit1: TEdit;
    ComboBox2: TComboBox;
    ComboBox1: TComboBox;
    Panel2: TPanel;
    Panel3: TPanel;
    DBGrid1: TDBGrid;
    DBNavigator1: TDBNavigator;
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
    procedure ComboBox2Change(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  deletegradeForm: TdeletegradeForm;

implementation
uses datamoduleunit;

{$R *.dfm}

procedure TdeletegradeForm.FormCreate(Sender: TObject);

var year,month,day:word;
     n:integer;
     thisyear:integer;
begin
  DecodeDate(now, Year, Month, Day);
  thisyear:=round(year);
for n:=1 to 20 do
   begin
    combobox1.Items.Add(inttostr(thisyear));
    thisyear:=thisyear-1;
   end;
 combobox1.ItemIndex:=-1;
end;

procedure TdeletegradeForm.ComboBox1Change(Sender: TObject);
begin
combobox2.Items.Clear;
combobox2.Text:='';
  with datamodule1.queryall do
    begin
     SQL.Clear;
     sql.Add('select distinct cname from grade where year=:year');
     Parameters.ParamByName('year').Value:=strtoint(combobox1.Text);
     prepared;
     open;
     if RecordCount> 0 then
     while  not eof  do
        begin
         combobox2.Items.Add( FieldByName('cname').AsString);
         next;
        end
      else combobox2.Items.Add( '<无记录>');
     close;
     end;
 with datamodule1.queryall do
    begin
     close;
     SQL.Clear;
     sql.Add('select * from grade where year=:year  ');
     Parameters.ParamByName('year').Value:=strtoint(combobox1.Text);
     prepared;
     open;
   end;

end;

procedure TdeletegradeForm.ComboBox2Change(Sender: TObject);
var temp:string;
begin

if trim(edit1.Text)<>'' then
  begin
  temp:=format('无法定位到指定的记录: [%s, %s, %s  ]'
+#13+'可能记录不存在于数据库中！',[trim(edit1.Text),combobox1.Text,combobox2.Text]);
    with datamodule1.queryall do
      begin
       if not locate('sno;cname;year',vararrayof([edit1.Text,combobox2.Text,combobox1.Text]),[]) then
            messagebox (handle,pchar(temp),'警告',mb_ok) ;
      end;
  end;
end;

procedure TdeletegradeForm.FormClose(Sender: TObject;
  var Action: TCloseAction);
begin
datamodule1.tablegrade.Close;
end;

end.